Men are the friskiest drivers
The firm's "saucy motoring secrets survey" reveals the statistic while 37 per cent of women admit to the same.
Sadly however, having an argument is a more likely pursuit, with nearly 55 per cent of men and almost 57 per cent of women fighting with their loved ones while in the car.
Women voted Audi drivers the sexiest male drivers (21 per cent), however men find women sexiest when they drive a Mini (19 per cent).
Male BMW drivers are considered second sexiest by women (19 per cent), followed jointly by Mercedes and Porsche drivers (six per cent). Men's second choice was female Audi drivers (12 per cent), followed closely by women who drive BMWs (10 per cent).
Gareth Kloet, head of car insurance at Confused.com said: "The results of this demonstrate that we truly are a nation of car lovers in every sense of the word.
"The number of men and women who tell us they have had sex in their cars has increased since last year's poll: 37 per cent of women (compared with 30 per cent last year) and 50 per cent of men (compared with 48 per cent last year)."